The present invention generally relates to medical endoscopes having elongated shafts and sealed housings that define a working passage, the working passage having a lateral branch passage for connection to a flow line.
Endoscopes of this type, which is referred to as solid shaft type, are used, for instance, in laparoscopy or in the field of urology as a nephroscope and ureteroscope. The working passage, which passes through the entire length of the endoscope, is open at its ends and is used for introducing working instruments through the length of the endoscope to the operational region. The housing sealingly surrounding the working passage accommodates devices in its interior which are required for operation of the endoscope and which must be protected from moisture during operation of the endoscope and, particularly, steam and moisture during the subsequent sterilization of the endoscope. Such devices are, in particular, an optical system, an illumination device, for instance in the form of the conventional light guiding fiber bundle, or other e.g. electronic devices. A very good seal of the housing is of importance for a long-life construction of the endoscope.
The working passage in instruments of the type referred to above is also used as a flow conduit to communicate fluid to/from the operational region. For this purpose, a lateral branch passage is provided to which further flow lines may be connected. The proximal end of the working passage can be commonly closed with a valve and the branch passage can be commonly opened with a further valve in order to pump, for example, flushing liquid to the operational region through the distal portion of the branch passage or to draw fluid from the operational region. Gas, for instance, can also be exhausted or admitted through the flow line.
Such endoscopes can also have an additional outer shaft over the main shaft which is disposed around the distal insertion region of the main shaft and is removably coupled to it, for instance, with a coupling on the main body proximately adjoining the shaft. The space between the main shaft and outer shaft can be used as a flushing or suction passage, for which purpose a further branch passage is provided on the outer shaft connected to the space between the shafts.
In known endoscopes, the branch passage is connected to the portion of the working passage extending proximally beyond the housing. This type of connection offers the advantage of a simple construction but has the disadvantage that a hose hanging from the branch passage while working with the endoscope is situated too proximally. Therefore, the branch passage at this position loads the endoscope with its weight too far proximally behind the center of gravity of the device. Moreover, placing the branch passage at this location situates it in the proximal region, which is required by the operator for gripping purposes and for viewing at the ocular of the optical system.
In a different type of endoscope which is used as a urological resectoscope and which is disclosed in DE 41 01 472 C1, a shaft is provided with a rotationally coupled outer shaft. Two branch passages are provided on the outer shaft, of which one is connected to the space between the shafts and the other is connected via a sealed annular passage and an opening in the inner shaft to the latter. This device is designed in accordance with the hollow shaft principle and thus does not have the problem of a sealed housing in the vicinity of the branch passages.
It is the object of the present invention to construct an endoscope of the type referred to above such that the branch passage and associated hoses impair working with the endoscope to a lesser extent.
In accordance with the present invention, the branch passage is not provided directly on the working passage in its region projecting proximally beyond the housing but in the region of the housing and passing through it. Therefore, the branch passage is disposed substantially further distally, particularly distally of the outlets of the optical system and of the light guide. Hoses to be attached to the branch passage can be moved together with the other lines extending away, e.g. a light guide cable, into a favorably balanced position with respect to the center of gravity. The branch passage is also situated remote from the working region of the operator. Disruptions by the branch passage and hoses disposed thereon are substantially limited. One can work substantially more easily and simply with the endoscope in accordance with the invention.
In further accordance with the present invention, a sealing body surrounds the branch passage and is disposed between the working passage and the housing. As such, the necessary seal of the branch passage with respect to the interior of the housing can be effected in a constructionally simple manner.
The branch passage can be fixedly arranged on the housing. However, in further accordance with the present invention, an inner portion communicates with an inner peripheral passage in a ring that is disposed around the housing. Therefore, the branch passage is pivotable about the axis of the endoscope so that it can be set at a favorable angle in all rotary positions of the endoscope, for instance pointing downwardly.